Tools used for grinding, cutting and machining, are often manufactured with abrasive surface coatings. Manufacturers of such tools are constantly looking for ways to improve the functionality and performance of such tools. There is a broad spectrum of tools used for such purposes, such as drill bits, saws, knives and grinding wheels. Also, large-area and complex-shaped tools are used for a variety of functions such as tunneling, oil well drilling and bulldozing. In addition to improving tool performance, manufacturers are continually striving for improved methods of fabricating such tools. In particular, there is a common need in the industry to find improved methods of fabricating abrasive surface coatings for tools.
Numerous methods have been devised to form abrasive surface coatings on tools. Generally, rigid abrasive tools are manufactured by applying abrasive particles, mixed with a bonding agent, to the working surface of the tool. The "working surface," as used herein, is the tool surface which performs the cutting, grinding, or machining. For some applications, the abrasive/bonding composite material is formed and solidified prior to attachment to the working surface of the tool by an adhesive backing. For other applications, the composite material is formed and then applied, as a slurry, to the working surface of the tool, where the slurry subsequently solidifies and cures. For example, U.S. Pat. No. 5,551,959 to Martin et al. describes a high-performance abrasive coating which is manufactured by incorporating variations of these general methods. These methods are expensive and labor intensive. In addition, they are not amenable to coating large-area and complex-shaped tool surfaces.
Still other methods have been developed which make it more feasible to deposit abrasive coatings to complex shaped surfaces, by depositing the abrasive coating as a chemical vapor using either physical vapor deposition (PVD) or chemical vapor deposition (CVD). For instance, U.S. Pat. No. 5,588,975 to Hammond et al. describes a method for manufacturing a grinding tool in which the abrasive coating of the working surface of the tool is applied as a plasma. However, these methods have inherent limitations, such as the use of vacuum equipment, which limits the abrasive coating applications to small tool substrates. In addition, such methods are expensive and not amenable to an automated production environment.
For the foregoing reasons, it would be desirable to have an efficient and inexpensive method for depositing high-performance abrasive coatings on tools, including those having large surface areas and/or complex surface shapes. The method should provide a means for applying a variety of abrasive coating compositions to different types of tools, without producing byproducts which are harmful to the environment. Furthermore, the method should be flexible enough to be used in an efficient automated assembly environment.